1. Field of the Invention
The present invention relates to a plug for speaker cables, and a speaker terminal by which the speaker cables for respective channels can be connected easily and exactly to the multichannel speaker terminal in an audiovisual field such as a home theater system and to a speaker terminal system composed of the plug and the terminals.
2. Description of the Related Art
In recent years, the so-called home theater system by which the impact and sense of movie-like reality, that is, the sensation of a movie theater, has become widely prevalent. In a home theater system, a screen image is projected on a big screen in cooperation with acoustic effects in a delicate, highly real, and powerful manner, delivered from multichannel speakers, e.g., 5.1 channel speakers, which correspond to the screen image so that spectators can enjoy a screen image and acoustic effects which cannot be achieved by a conventional audio system. Accordingly, such a powerful home theater system as mentioned above is expected to become widely used rapidly.
In the above-described system, however, since a number of loud speakers having various sizes are used for realizing such impressive acoustic effects in multiple channels, there is such a problem that not only are connecting operations complicated just in the case where the connection for respective loud speakers is made by the use of terminals of a conventional lever type or the like, but also erroneous connection arises easily because the system involves multiple channels and multiple speakers.
The present invention has been made in view of the facts described above. Accordingly, objects of the present invention is to provide a plug for speaker cables by which loud speakers can be connected easily with the appropriate speaker terminals of an amplifier or the like, so that there arises no erroneous connection or the like in an audio system, such as the above-described home theater system, wherein loud speakers of various sizes are used in multiple channels and to provide speaker terminals disposed on an amplifier side for connecting to the plug, and to provide a terminal system provided with the above-described plug and terminals.
According to the present invention, a plug for the speaker cables of the invention comprises a plug main body involving terminal loading slots for positive and negative polarities on the front thereof, loading slots for cables in response to both polarities on the rear thereof, and a hollow inside thereof; tongues for holding terminals functioning to hold speaker terminals inserted from the terminal loading slots from the external surface thereof by spring action; tongues for holding cables connected to the tongues for holding terminals and functioning to hold stranded wires of speaker cables inserted from the cable loading slots from the external surface thereof by spring action; and the tongues for holding cables being formed so as to expand sections for holding cables by operating pieces disposed so as to be exposed outside the plug main body, respectively.
Furthermore, according to the present invention, in the plug for speaker cables as described above, an engaging lever may be disposed on an external surface of a side on which terminal loading slots are provided, and the engaging lever is inserted into a plug loading slot while bending elastically to be engaged when the plug is inserted into the plug loading slot provided with output terminals or input terminals for loud speakers disposed on an amplifier or the like. Moreover, according to the present invention, in the plug for speaker cables as described above, a right sectional shape of the plug for speaker cables may be formed into vertically or horizontally asymmetrical contours, and a front shape of a plug loading slot on an amplifier or the like into which the plug is to be inserted is formed into an inside shape having the same section as that of an outside shape in the right section of the plug. Since a plug for speaker cables according to the present invention has been constituted as described above, connection polarities thereof are never inverted.
Furthermore, a speaker terminal according to the present invention comprises one or more plug loading slot having such a mode that the front end of which is opened into a substantially same sectional shape as a right sectional contour of a plug for speaker cables to be inserted to define the right sectional shape of an opening and recessed correspondingly; an engaging projection for latching and supporting an engaging portion of an engaging lever as part of a plug to be inserted and that is disposed on the front end of an opening edge in the respective plug loading slots; and contact pieces in terminals of positive and negative poles for a speaker being disposed on the inmost recessed wall surface of the plug loading slots so as to be horizontal with respect to the front end of the opening. Here, extreme ends of contact pieces in terminals of positive and negative poles may be disposed with a difference in their distances from the front end of the opening in the plug loading slots. Since a speaker terminal according to the present invention has been constituted as described above, noise can be avoided at the time of connection thereof. Also, it is arranged such that a test finger is not in contact with the contact piece in cooperation with a contour of the opening.
In the speaker terminal according to the present invention as described above, the respective plug loading slots for right and left channels may be disposed such that both of the plug loading slots are in symmetrical disposition. Since a speaker terminal according to the present invention has been constituted as described above, respective plug loading slots for right and left channels in plural channels can be arranged with good space efficiency, whereby the area for a terminal for connecting loud speakers can be reduced.
Further, in the speaker terminal according to the present invention as described above, front external surfaces of the plug loading slots for respective channels may be colored differently. Thus, erroneous connection of channels can be avoided. Besides, each shield plate may be disposed on the front surface thereof, except for each of the plug loading slots. Thus, a countermeasure for noise can be established.